Spring steel wire with improved permanent deformation resistance and manufacturing method therefor
AssigneePosco
InventorsYoungsoo CHUN, Myungsoo CHOI, Sewon PARK, Daehwan KIM
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Abstract
A spring steel wire with improved permanent deformation resistance, according to an embodiment, comprises, by weight percent, C: 0.39-0.51%, Si: 1.30-1.70%, Mn: 0.20-0.45%, P: 0.015% or less, S: 0.020% or less, Cr: 0.50-0.80%, Ti: 0.015-0.030%, B: 0.0010-0.0040%, N: 0.003-0.015%, the remainders being Fe and inevitable impurities, wherein the spring steel wire may have a dislocation density in the range of 6.0×1013 to 3.0×1014 m−2.
Claims7
A spring steel wire with improved permanent deformation resistance, comprising, in percent by weight (wt %), 0.39 to 0.51% of C, 1.30 to 1.70% of Si, 0.20 to 0.45% of Mn, 0.015% or less of P, 0.020% or less of S, 0.50 to 0.80% of Cr, 0.015 to 0.030% of Ti, 0.0010 to 0.0040% of B, 0.003 to 0.015% of N, the remainder being Fe and inevitable impurities, and
- having a dislocation density of 6.0×1013 to 3.0×1014 m−2.
A method of manufacturing a spring steel wire with improved permanent deformation resistance, the method comprising:
- preparing a billet comprising, in percent by weight (wt %), 0.39 to 0.51% of C, 1.30 to 1.70% of Si, 0.20 to 0.45% of Mn, 0.015% or less of P, 0.020% or less of S, 0.50 to 0.80% of Cr, 0.015 to 0.030% of Ti, 0.0010 to 0.0040% of B, 0.003 to 0.015% of N, the remainder being Fe and inevitable impurities;
- finish rolling the billet at 880 to 980° C. to produce a wire rod;
- cooling the wire rod;
- reheating the cooled wire rod to a temperature of 900 to 980° C. and then quenching the reheated wire rod;
- and
- tempering the quenched wire rod at a temperature of 220 to 300° C.
Dependencies are inferred from the claim text.